Stranger was pretty weak, and the beginning of his turn to navel-gazing. I had to really push my way to the end. Talk talk talk. Like the preachiest of Ayn Rand.
Am on Double Star now, and Gods of Mars by ERB
One of the very best. Heinlein was a thinker. The ending is pretty cool, and you wonder why you didn't realize it. And you are right - - Heinlein's best stuff was the so-called "juvenile" sci-fi. I read all of Heinlein's books in the '60s and I occasionaly enjoy re-reading them today. 'Door into Summer', 'Puppet Masters', and my personal favorite, 'Tunnel in the Sky'. Great, great stuff.
Grew up as a kid reading lots of SF...started reading it seriously when I was in 3rd grade...started reading Heinlein when I was in 5th grade...(mostly his future history stories)...was shaped by people like him and Asimov and John Campbell back at Analog....
But I always sort of prefered Moon Is a Harsh Mistress to Stranger....